Molybdenum-based intermetallics are currently being developed for high temperature application ( > 1000°C) in advanced fossil energy combustion systems. The goal is to maintain the desired high-temperature mechanical properties while also achieving the required high-temperature oxidation/hot corrosion resistance. In this research, molybdenum alloys were investigated using high temperature moire interferometry. Three-point-bending tests were conducted, and detailed fracture behavior around crack tip was investigated at both room temperature and elevated temperature. Grain boundary sliding was observed through high resolution in-plane deformation fields. For each test, a follow-up fractography and microstructural analyses were carried out. Test results showed that molybdenum alloy with silicide has higher toughness and enhanced grain boundary strength at elevated temperature. The effect of oxygen on grain boundary cohesive strength of Mo alloy was also studied using atomistic modeling and simulations.
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